How to reproduce:
1. Open users attached project and "scene" level (make sure that you are connected to internet)
2. Enter playmode
3. Click on "Start Download" button, the download will be automatically aborted on 30%

Expected result: No assertion is thrown
Actual result: Assertion failed on expression: 'm_UncompressedBlocksOffsets[blockInd] <= from + dstPos && m_UncompressedBlocksOffsets[blockInd] + uncompressedBlockSize >= from + dstPos'

Notes:
1. Did happen with LZ4 compression, did not happen when BuildAssetBundleOptions were set to None
2. The code aborts the request when it hits about 30%. The assertion failed message only seems to appear when it's aborted at specific progress amounts
3. Seems to be Editor-only, as Assertion did not reproduce on Standalone Windows player

Regression introduced in - 2017.3.0b4
Reproducible with - 2018.2.0a4, 2018.1.0b11, 2017.3.1p3, 2017.3.0b4
Not reproducible with - 2017.3.0b3